account added address admin associate button buy email field motions paypal profile sign thru

I have added an email to my paypal account and went thru the motions for a buy now button with e-junkie.
Where does e-junkie associate the paypal email with the e-junkie button? Is it from my sign in email address? or is there somewhere else?

We use the PayPal email you enter in E-junkie admin > Profile in the field which says "PayPal email".